My friend is still on vacation, but this is the general idea, from camaros.net, a relevant thread:
"Whatever starter you use you might want to make sure IF IT IS A STOCK TYPE that it has the big field coils in it!!
You can tell if it does b/c back on it's end opposite the snout, it will have a 3/4" long copper spacer piece that bolts the field coil strap that comes out of the housing to the back of the Bendix. This is b/c the field coils are longer and are heavy-duty!! (I.e., more torque output!!!)...
Once, I just took my old 350's big flywheel starter to the parts house and told them I wanted a h/d one that matched my snout and I ended up with a rebuilt h/d 454 vette starter.. The parts-person dug around opening boxes for about five minutes before he found it....
That's the kind of service I look for in a good parts store!!!!!
You can read the whole thread at:http://www.camaros.net/forums/showthread.php?t=50981&highlight=starter+interchange
Hope this helps, sorry I could not do better ( for now at least). I guess the kay is whether or not your block is drilled for the desired starter .